Please help me to decide which parts

I'm planning to upgrade my video card to the BFG GeForce 8800 GT OC. To do so, however, I'll need to buy a new motherboard because my current one does not have a PCI-Express slot. I'll also need a new power supply. I have very little knowledge of computer parts, so I'm asking for advice on which motherboard and power supply I should get. Both the motherboard and the power supply must be good enough to run the video card smoothly. I might also upgrade my memory; my current ram is 512MB, so any suggestions on which ram would be appreciated. I'm willing to pay around $150 each for the motherboard/powersupply, and around $80 for the ram. I'm a hardcore gamer, so base your suggestions off that as well.

Heres the thing though: I'll only be shopping for the parts at my local electronics store, which is www.NCIX.COM. So the parts that you recommend for me MUST be sold at that store.

Thanks.

what cpu socket do you have?intel 775 or amd am2?if u using intel i suggest take asus mobo P35K its around $150, if your cpu amd then take Abit AX78($99).for the psu go with Silverstone Strider ST56F(around $97) with 560 w power,it performance is good,stable and supports 80+ efficiency.for the ram take Team 2x1GB DDR 2 800 Elite, heatspreader($65)it's performance is awesome almost same performance with the lowest DDR3 ram.but i'll leave it up to you,right?